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RUSH (Reliable Ultra-low-latency Streaming over HTTP)¶
RUSH — Reliable Ultra-low-latency Streaming over HTTP — is Meta's in-house, QUIC-based live-streaming ingest protocol, built to move past RTMP. For "nearly a decade" it was the transport under Meta's live streaming video, and it is the direct predecessor to MoQ: RUSH "proved that QUIC could carry live media at scale," and the lessons from running it in production "are part of what shaped our bet on MoQ." (Draft spec: draft-kpugin-rush.)
As of 2026, RUSH is being replaced by MoQ for Instagram Live ingest — but it does not disappear immediately: during the migration the backend still speaks RUSH, and MoQ frames are translated to RUSH at the edge so nothing downstream changes. (Source: sources/2026-10-12-meta-shipping-media-over-quic-at-meta-scale-for-instagram-live-ingest)
Why Meta is moving off it¶
RUSH was "stable and performant at scale for nearly a decade," so the motive is governance, not failure: RUSH is a protocol "operated primarily by Meta," whereas MoQ shifts development to a shared IETF standards effort where multiple implementers test interoperability and improve the specification, instead of Meta evolving the transport largely on its own. In other words, RUSH "was falling behind the open ecosystem." (Source: sources/2026-10-12-meta-shipping-media-over-quic-at-meta-scale-for-instagram-live-ingest)
Role during the MoQ migration¶
- Backend lingua franca — the existing live backend understands RUSH framing; MoQ ingest connections terminate on edge endpoints where a translation layer converts MoQ → RUSH, leaving the backend untouched while the client transport is swapped (an edge-translation / strangler-fig step).
- Per-broadcast switch — a single config parameter selects MoQ or RUSH for a given broadcast, so the two run in parallel and the rollout is reversible.
- TCP fallback expedient — Meta currently "lean[s] on RUSH's existing TCP fallback" for networks where QUIC's UDP/443 is blocked. The plan is to adopt a standards-based TCP fallback for MoQ (QMUX) so a blocked network "no longer forces a second protocol," eventually opening the door to retire RUSH.
Seen in¶
- sources/2026-10-12-meta-shipping-media-over-quic-at-meta-scale-for-instagram-live-ingest — RUSH is the nearly-decade-old QUIC-based protocol Meta is replacing with MoQ for Instagram Live ingest; it is simultaneously the migration's backend format (via edge translation) and TCP-fallback expedient, and its production lessons shaped the MoQ bet. The MoQ path "matched RUSH across the streaming-quality indicators and reliability measures used for the rollout" — parity against RUSH was the explicit success bar.